Apparatus for and method of drying leather without the use of paste



' IZZY; r"

Aug. 24, 1954 M. HOUGHTON 2,686,976

APPARATUS FOR AND METHOD OF DRYING LEATHER WITHOUT THE USE OF PASTE Filed Dec. 15, 1951 2 Sheets-Sheet l V Inventor Wilda m M Hazy/lion 15 hi) ii-orrz Aug. 24, 1954 Filed Dec. 15, 1951 HOUGHTON W. M. APPARATUS FOR AND LEATHER WITHOUT LEA THEA METHOD OF DRYING THE USE OF PASTE 2 Sheets-Sheet 2.

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Inventor M'Z/[amM f/oqg/z ton 4? h 0 l4 Patented Aug. 24, 1954 APPARATUS FOR AND METHOD OF DRYING LEATHER WITHOUT THE USE OF PASTE William M. Houghton, Marblehead, Mass, as-

signor to United Shoe Machinery Corporation,

Flemington,

N. J a corporation of New Jersey Application December 15, 1951, Serial No. 261,899

8 Claims.

This invention relates to apparatus for and a methodof drying tanned hides and skins, and more particularly to an improved apparatus for and a method of slicking out leather and drying the same in spread-out condition.

Tanned hides or skins, while undergoing their various stages of treatment, and depending upon their nature and use, are dried at least once and usually several times. It has heretofore been the practice to stretch spread-out or slicked-out work pieces individually on frames or plates as a preliminary to the drying operation. Each work piece undergoes considerable shrinkage during drying and, in order to avoid this result, each piece is usually toggled to a frame or pasted to a plate to maintain the work in extended condition against the strong tendency of the leather to contract during the drying.

When glass or porcelainized metal plates are used with paste as the attachingmedium excel.-

lent results are secured in that the work is held in its extended condition and the grain surface being maintained in contact with the plate is made smooth and. the over-all quality of the work is most satisfactory. It has been proven, however, that the paste method, which is preferred over the use of toggles, is not suitable for some leathers for a number of reasons the most common one being that the paste adheres to the leather after drying and its removal entails considerable expense and difiiculty. Another reason is that the paste method is highly impractical for drying thin leathers. It would be highly advantageous if, in the use of plates, paste'as well as toggles could be dispensed with in maintaining the leather in its stretched-out condition to secure a product as excellent as that heretofore produced by the paste method.

It is obvious that if wet leather is to be dried with efliciency, using drying plates and without an adhesive paste, a novel manner or means must be supplied for holding the work in extended condition and that heat must be applied in an amount well controlled to avoid leather deterioration. A glass drying plate wets readily and holds wet work in its slieked-out position without paste. Such a plate is notsatisfactory, however, as its thickness must be such as to give sufiicient strength to avoid breakage. The drying of hides and skins requires large area plates and the large size necessitates such a thickness that the poor heat conductivity of a suitable glass plate will either cause overheating of the leather (because of lack of heat control) or too lengthy a drying period. Porcelainized metal plates are wettable and wet leather may therefore success fully be slicked out upon them. They also transfer heat readily. Such plates do chip in use however and have a major disadvantage in that their holding power, per se, for leather becoming progressively drier, becomes inadequate and has heretofore been necessarily supplemented by the use of toggles or paste as is also true in the case of glass plates. Metal plates with bright surfaces transfer heat excellently but such surfaces do not become wet so as to cause wet leather to adhere to them.

One object of the invention is to provide a novel apparatus for drying leather in the use of which apparatus the leather is maintained in a stretched-out condition without the use of paste, handling of the work is facilitated and drying time is shortened.

Another object of the invention is to provide a novel method of drying leather in which heat is applied to one side of the leather while the latter is slicked out and maintained in stretched-out condition without the use of paste and with evacuation of water vapor from the other side of the leather.

For the purpose in view, a metallic plate with one non-corrodible surface roughened to be sufficiently wettable and preferably having a matte character is provided to cooperate with a flexible porous material that is vapor transmissive when Wet, the arrangement being such that a wet work piece interposed and pressed between the sufiiciently wettable surface or roughened surface of a matte character and the porous material may be heated through the plate and simultaneously water vapor may be evacuated through the porous material. Preferably, the plate is of stainless steel with the matte. finish being produced by sandblasting and the porous material is of woven wire with a fine mesh adapted to contact the flesh side of the work.

The invention will now be more particularly described by reference to the accompanying drawings and thereafter pointed out in the claims.

In the drawings,

Fig. 1 is a side view of an apparatus embodying the present invention;

Fig. 2 is a front elevation view of the apparatus shown in Fig. 1; and

Fig. 3 is an enlarged sectional view taken along the line III--III of Fig. 2.

The main frame of the apparatus includes two horizontal channel bars l0 and I2 (Fig. 2) joined together by two horizontal tubes M and I6 (Fig. 1) welded thereto. Bolted to the channel bars Ill and I2 and toward the front of the apparatus are two short vertical channel bars l8 and 20 and two longer channel bars only one of which, 22, is shown in the drawings. The upwardly extending channel bars serve to support a rectangular frame made up of angle bars 2 and this rectangular frame is supported in a plane inclined at an angle to the vertical. The inclined frame serves as a support for a steel plate 26 and rock wool insulation 21 permanently affixed thereto by means not shown. The rectangular border of the plate 26 is interposed between a frame-like member 28 and the angle bars 24. This frame like member 28 serves to hold a metallic plate 3!] in permanent and spaced relation with the steel plate 26. The exposed or upwardly presented surface of the steel plate 30 is provided with a roughened surface of a matte character as will be further explained.

At the top of the rectangular frame made up of the angle bars 24 are two brackets 32 and 3a to which are pivoted two upwardly extending plate members 36 and 38 respectively. At the upper ends of the plate members 36 and 38 are pivoted two rods 40 and 42 which serve to support counterbalance weights, only one weight M being depicted in the drawings.

The plates 36 and 38 extend downwardly and to the left of the machine frames as viewed in Fig. 1 and are joined to plates 48 and 5t which are held by means of brackets 52 and 5 3 respectively to two suction manifold sections 55 and 58. These two sections are joined by a third section 65% and these three sections form a structure in the shape of an H and they are joined to a steel plate 62 which is cut away in the area beneath the sections so that communication is had between the sections 56, 58 and 60 through the plate 62. The plate 62 is also provided with an upstanding peripheral flange 6*- to lend rigidity and a second outwardly inclined flange 66 to which is joined a flexible rubber sealing strip '68.

Beneath and along the margins of the plate 62 and contiguous with the inclined flange 66 are attached two layers of a vapor-transmissive material such as metallic screens lii. These screens may be in one or more layers and the finest mesh is placed most remote from the plate 62. Interposed between the plate 62 and this porous material I0 is a resilient member 12 preferably of rubber having grooves M and through passages 76. The passages 16 are so placed as to insure communication between the manifolds 56, 58 and Gil with the passages 14 and hence the interstices of the flexible screen means or porous material E0.

The lower ends of the plates 48 and 50 are provided with a handle member in the form of a tube 30.

The manifold Gil is provided with an elbow 82 to which is connected a valve 84 and a flexible conduit 86 which leads to a system or pump for producing a vacuum. A valve 81 is connected to the elbow 82 and is adapted to serve as a vent to the atmosphere.

At a lower part of the plate 26 a conduit 88 is provided by means of which a heating fluid 89 such as hot water may be introduced through the plate 26 and into the space defined by the plate 26 and the plate 30. A conduit 90 is provided at the top of the plate 26 through which hot water may be drawn away from the space fed by the pipe 88. It will be understood that the frame 28 is so constructed as to form together with the plates 26, 30 a sealed space for the hot water.

To prevent the counterbalance weights from swinging, each one is provided with a link 92 pivoted to it and also to a bracket 94 on the base of the machine.

In operating the apparatus and in order to prepare it for receiving a work piece to be dried, the handle 89 is grasped and the plate 62, together with the porous material 10, and the attendant parts are lifted with the aid of the counterbalancing weights clear of the metallic plate 30. The weights are such as to lower into the positions illustrated in dash lines in Fig. 1 in which case they serve to hold the movable frame in an approximately horizontal position.

Assuming that hot water is being circulated between the space defined by the fixed plates 26 and 30 a wet leather work piece W (Fig. 3) is slicked out and down upon the exposed, non-corrodible and upwardly presented surface of the plate 30 which surface is of such a roughened nature as to have an increased wettability. The operator finds that the work may be easily slicked out by using his hands, a wooden blade or some equivalent instrument. Each hide and skin is usually possessed of a highly irregular contour and if the surface of the plate 30 is not wettable, the edges will detach themselves first and this, of course, cannot be permitted. With a suffi ciently; wettable surface the main body and the edges of each work piece remain smoothly in position for an interval of time (prior to the next 1 step) which is more than ample for the purposes of the present invention.

With the wet leather work piece W (grain side down) suitably slicked out, and partially held by gravity (preferably but not of necessity) on the plate 3% due to the inclination of the latter, the handle 8%] is pulled down to bring the porous member or screens Til into contact with the stretched-out work piece W and to press the flexible rubber sealing strip 68 against the plate 39. Suction is then applied to the manifolds 56, 53 and 60 by the opening of the valve 84 (valve 81 being closed) with the result that the work piece W is quickly dried. Vapor is drawn from the leather W, through the flexible screens 10, grooves M and passages '15. The wettability or holding power of the surface of the plate 30 is immaterial after the apparatus is closed as the pressure ap-' plied by the porous material or screens l0 holds the progressively drying work piece in its extended condition.

After a suitable interval, the length of which is easily determined by experience with the par-' ticular type of leather and the degree of dryness desired, the apparatus may again be opened by first closing the valve 8d and releasing the vacuum (with opening of the vent valve 81) and then by lifting on the handle 80. As the work piece W is thus released, it either falls from the plate 30 or it may easily be stripped therefrom in its dry and clean condition and with an excellent grain surface. The drying interval has been found to be surprisingly short, a fact which is. of importance in a tannery.

The vacuum created in the confined space occupied by the leather during the drying operation expedites the emission of the water from the leather by lowering the evaporation point and also cooperates with the'porous means it to hold the work piece W snugly and firmly against the plate 30 regardless of the possible variations in the thickness or dryness of the work.

It is preferred but not essential that the grain surface of the leather be placed against the plate heat transferring ability. The plate may be of Monel metal, plated steel, laminated. metal, stainless steel or porcelainized metal. The surface of the plate which is to contact the work must be wettable, as heretofore stated. It should resist the chemical action of leather and those substances customarily used in the tanning of leather. If metal is provided with a roughened surface 01' a matte character it is sufliciently wettable and will serve to hold the leather. Preferably the surface is of sandblasted stainless steel.

No paste having been used, each dried work piece is easily removed from the apparatus and it is removed in clean condition thereby retaining advantages of the conventional pasting method such as the retention of area and eliminating the disadvantages thereof. The porous material, which is preferably of woven wire,is obviously of a very fine mesh at the interface with the work' to eliminate any possibility of marking the leather and when made of such fine mesh it is surprising that the mesh is not clogged, particularly when the nature of wet leather is considered.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of drying leather which comprises slicking out a wet work piece upon one surface of a metallic plate, said surface being of non-corrodible material, wettable and therefore adherent to wet leather, applying a vapor transmissive material to the exposed side of said work piece, heating the said work piece through said plate and simultaneously with the heating evacuating vapor from said work piece through said material.

2. The method of drying leather which comprises slicking out a wet work piece upon and with its grain side in contact with one surface of ,a metallic plate, said surface having a matte finish, applying a vapor transmissive material to the exposed side of said work piece with pressure, heating the work piece through said plate while it is pressed against said plate and simultaneously evacuating vapor from said work piece through said material.

3. The method of drying leather which comprises slicking out a wet work piece upon one noncorrodiblesurface of a plate having a main body of metal, said surface being sandblasted to give a matte finish for retaining the wet work piece in position, applying a vapor transmissive material to the exposed side of said work piece, heating the work piece through said plate and simultaneously evacuating vapor from said work piece through said material.

4. The method of drying leather which comprises slicking out a wet work piece upon and with its grain side in contact with a sandblasted surface of a stainless steel plate, said plate being inclined to the vertical, applying a vapor transmissive material to the exposed side of said work piece, heating the work piece through said plate and simultaneously evacuating vapor from said work piece through said material.

5. Apparatus for drying leather including a main frame supporting a heating means and a stainless steel plate upon which said heating means may be effective, said plate being inclined to the vertical and having one side sandblasted and upwardly presented upon which a wet work piece may be slicked out, a counterbalanced frame pivoted to said main frame and supporting screen means and a resilient member with grooves backing up said screen means, and at least one suction manifold on said counterbalanced frame connected to the interstices of said screen by way of said grooves, the said counterbalanced frame being movable toward said steel plate to cause said screen means and said sandblasted side to contact opposite sides of a work piece when the latter is interposed between them.

6. A leather drying apparatus having, in combination, a flat metallic plate the exposed surface of which has been roughened sufficiently so that a wet leather work piece stretched out thereon will be maintained in its distended condition by the cohesive action of the fluid contained in said work piece, means for heating said plate, and means cooperating with said plate for holding the work piece in its distended condition on said plate during the drying operation while permitting escape of moisture therefrom.

7. A leather drying apparatus comprising a rigid metallic, impermeable, substantially flat plate for supporting a wet leather work piece to be dried, said plate having a roughened work supporting surface providing an efiective area substantially greater than the apparent area so that a stretched out wet leather work piece will remain on said plate in its distended condition prior to being dried, means for heating said plate, and means cooperating with the plate for holding the work piece in said distended condition during the drying operation while permitting escape of the moisture therefrom.

8. A leather drying apparatus having, in combination, a flat corrosion resistant metallic plate the exposed surface of which has been roughened sufficiently so that a wet leather work piece stretched out thereon will be maintained in its distended condition by the cohesive action of the liquid contained in said work piece, means for heating said plate, and means for maintaining said work piece in it distended condition during the drying operation, said means comprising a flexible, resiliently mounted, foraminous sheet which covers an opening in an impermeable chamber which is adapted to be brought into cooperative relationship with said plate, means forming an air-tight seal when said plate and said chamber are in cooperative relationship, and means for exhausting air from said chamber to cause said foraminous sheet to hold the leather in its distended condition as moisture is drawn therefrom.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 271,858 Johnson Feb. 6, 1883 1,773,494 Millican Aug. 19, 1930 1,960,697 Cochran et al May 29, 1934 2,151,048 Rowe Mar, 21, 1939 2,566,581 Peterson Sept. 4, 1951 

